Apparatus for the manufacture of portland cement and similar products.



W. H. MASON.

APPARATUS FOR THE MANUFACTURE OF PORTLAND CEMENT AND SIMILAR PRODUCTS.

APPLICATION FILED MAY 2I, I914.

Patented Jan. 2, 1917.

2 SHEETS-SHEET I.

BY 063% Y ATTORNEYS WITNESSES W. H. IVIASON.

APPARATUS FOR THE MANUFACTURE OF PORTLAND CEMENT AND SIMILAR PRODUCTS.

APPLICATION FILED MAY 2I| I914.

Patented Jan. 2, 1917.

2 SHEETS SHEET 2 mm am INVENTOR W ATTQRNEYS WITNESSES TATES PATENT@FFIGE WILLIAM H. MASON, 01E EASTON, PENNSYLVANIA.

APPARATUS FOR THE MANUFACTURE OF PORTLAND CEMENT AND SIMILAR PRODUCTS.

To all whom it may concern Be it known that I, WILLIAM H. Mason, acitizen of the United States, and a resident of Easton, county ofNorthampton, and State of Pennsylvania, have invented certain new anduseful Improvements in Apparatus for the Manufacture of Portland Cementand Similar Products, of which the following is a specification.

According to the practice now usually followed in the manufacture ofPortjand cement, the cement forming materials are ground to extremefineness before their introduction into the rotary kiln. For grindingdry, expensive drying operations for driving off any surplus moisturewhich will interfere with dry grinding must be resorted to, so that thegrinding can be effectually carried on. With wet grinding much surpluswater must be added, the greater part of which accompanies the materialsinto the kiln and is only driven off in the kiln upon considerableexcess expenditure of energy in the form of heat.

In either case, whether ground dry or wet, the entire weight of materialintroduced into the kiln when ground preliminarily, including thesurplus weight afterward lost by driving off the carbon dioxid in thekiln, must be subjected to the grinding operation.

According to the present invention the cement forming material isintroduced into the kiln without preliminary grinding, the constituentsbeing subjected, preliminarily to their introduction into the kiln, onlyto' moderate and inexpensive size reduction, preferably so that thelargest particles will pass through a one-half inch screen orthereabout, though the precise extent of such preliminary size reductionis not material. These particles of cement forming material in the rawstate and containing more or less moisture, when subjected to the heatof the kiln, are ruptured and made friable by the efiects of heatthereon, including the sudden expansion of the contained moisture intosteam, and are substantially completely calcined by being passed throughthe calcining zone of the kiln and subjected to heated gases therein,where all or the greater part of the carbon dioxid is driven 0E, andsuch cement form- Specification of Letters Patent.

Patented Jan. 2,1917.

Application filed May 21, 1914. Serial No. 840,032.

ing material, before reaching the clinkering zone of the rotary cementkiln, while hot, without substantial reduction or loss of heat, andbeing reduced in weight by the elimination of carbon dioxid, and more orless broken down and rendered friable by the Various effects of the heatthereon, is subjected to a grinding operation and after being ground isdelivered to the clinkering zone of the kiln in finely divided formready for making perfect cement clinker. The last stages of calciningthe material may be, and preferably are, carried out during the grindingoperation. It will be seen that in this manner the expense and troubleof carrying on drying and dry grinding operations, or water grinding anddrivin off the surplus water in the kiln, are avoi ed. By driving offsubstantially all the carbon dioxid before grinding, the material to beground is substantially reduced in weight over the material which wouldhave to be subjected to preliminary grinding, and the breaking downeffect of the heat upon the particles of cement forming material andattrition upon one another in the rotary kiln is completely utilized,thus greatly reducing the grinding left to be done and the powerrequired for the work of grinding, and at the same time making itpossible to get the materials into a very finely divided or pulverizedcondition.

Other advantages of my invention will appear in the course of my furtherdescription, and with the foregoing and related objects in view myinvention consists in the parts, improvements and combinations hereinset forth and claimed.

In the accompanying drawings I have shown, for the purpose ofillustration only, several different forms of apparatus in which myinvention may be embodied.

In said drawings, forming part of this specification and wherein thesame reference numerals are uniformly applied to designate the sameparts, Figure 1 is a fragmentary plan view, with parts broken away forclearness of illustration, and showing a ball or tube mill arranged atone side of a rotary cement kiln for receiving material therefrom,grinding it and redelivering it to the kiln without substantial loss ofheat. Fig.

2 is a cross-sectional view taken on line 22 in Fig. 1. Fig. 3 is .across-sectional view taken on line 3-3 in Fig. 1. Fig. 4 is across-sectional view taken on line M in Fig. 1. Fig. 5 is a fragmentaryside view, with parts broken away, and illustrating a grinding millinterposed between two parts of a rotary cement kiln and in linetherewith so that a continuous passage is formed through the kiln andthe grinding mill, the grinding mill being arranged so that it may berotated separately from the kiln. Fig. 6 is a cross-sectional view takenon line 66 in Fig. 5. Fig. 7 is a fragmentary side view with partsbroken away and showing a grinding mill arranged between two parts of acement kiln and in line therewith so that the central opening throughthe mill is a continuation of the kiln bore, but the mill of Fig. 7 isformed substantially as a part of the rotary kiln and rotates at thesame speed. Fig. 8 is a view similar to F 7, but showing a grinding millsurrounding a rotary cement kiln and arranged to receive materialtherefrom and to deliver it thereto after grinding, and Fig. 9 is adiagrammatlc side view showing the preferred disposition of the grindingapparatus with respect to a rotary cement kiln.

Having reference to the apparatus lllllS- trated in Figs. 1 to 4, and'which illustrates howmy improvements are preferably applied to an oldkiln already installed, the reference numeral 10 is applied to indlcatethe kiln generally, and the same comprises the two parts 11 and 12, fromthe former of which portions, 11, the material is taken before'grinding,and to the latter of which, 12, it is returned after grinding, thecalcining being carried on in the part 11 and the clinkering in the part12. 13 designates an inwardly extending flange formed, for example, offire brick, and separating the two portions 11 and 12 of the kiln, butbeing provided with a central opening 14 for the passage of the heatedgases of the kiln. Such flange 13, which may be of any form, serves as astop for the material passing downward through the section 11 of thekiln toward the section 12, and means are provided adjacent to saidflange or stop 13 for securing the discharge of the cement formingmaterial from the kiln. In the form shown the kiln section 11 isprovided with a plurality of openings 15'which open into a shell orjacket 16 surrounding the kiln in that neighborhood, and a plurality ofpaddles or wings 17 are provided on the exterior of the kiln section 11and fitting fairly closely within the shell or casing 16. A dischargeaperture 18 is provided for permitting the discharge of material fromthe shell or casing 16, and such material, after passing through theopenings 15 at or in the neighborhood of the bottom of the kiln section11, passes into the shell or casing 16 and is carried to the dischargeopening 18 by means of the paddles or wings 17 as the kiln is rotated.The shell or casing 16 is provided with an extension 19 which is incommunication with the feed opening 20 of the mill 21. Within the casing19, and preferably secured to rotate with the mill 21, are providedmeans for lifting the material from the bottom of the casing 19 anddelivering it to the interior of the mill 21. In the form shown, suchlifting means consists of spirally arranged feed chutes 22 communicatingat their mouths 23 with the interior of the casing19 at its periphery,and at their discharge ends 24 with the intake opening 20 of the mill21. The mill 21 may be an ordinary slug or ball mill and may contain, asis usual, a quantity of slugs or balls which may be of any material solong as they are heavy, resistant to wear, and capable of withstandinghigh heat. The

mill 21 at the end opposite the intake opening 20 is provided with theusual screen 25 through which the pulverized cement forming materialswill readily pass, but which will retain the balls, slugs or the like,used for grinding. At the end opposite the intake 20 means are providedfor redelivering the ground cement forming material to the. interior ofthe kiln. Such means may comprise radial wings or paddles 26 fittingclosely within the shell or jacket 27 for lifting the ground materialfrom the bottom of the jacket 27 to which it is delivered from the mill,the worm 28 arranged within the casing 29 which is a continuation of theshell or casing 27, the casing 30 arranged to encircle the kiln 10 andthe curved scoops or pockets 31 which are attached to the kiln 10 andcommunicate with the openings 32, through which openings the material isredelivered to the kiln below the flange 13. All the parts of thecasings are tightly and securely and closely connected together andclosely encircle the kiln in such manner as to prevent substantial inletof air, escape of dust and loss of heat by the material travelingtherethrough.

Any means of imparting rotation. to the kiln, the mill and the worm 28,may be used. In the illustration, the kiln and mill are shownchaindriven from suitable sources of power as 33 and 3 1, and the worm shafthas a pulley wheel 35 thereon for-attaching abelt or other suitabledriving means thereto. With the arrangement shown, comprising the Worm28, the cement forming material after grinding may be redelivered to thesection 12 of the kiln 10 adjacent to the flange 13. Other conveyingapparatus than the worm 28 may be used for this purpose, or the same maybe entirely dispensed with, if desired. A steam pipe 36 may be extendedinto the mill 21 for supplying steam tains a considerable amount ofmoisture, as

the presence of moisture here will permit such treatment without unduedust losses, the material not being finely ground when fed to the kiln.

In Fig. T have shown the two sections of the kiln 11 and 12 separatedsomewhat rial which has passed from one another and a grinding mill 21interposed therebetween, the central opening through such mill being a.continuation of the bore of the kiln 10 The mill 21 is so arranged withrespect to the sections 11 and '12 that it may be rotated separately andat such speed as may be required and so that there will be little or noopportunity for the escape or inlet of air or gases. In the form shown,the end walls 39 of the mill section are provided with annular grooves40, 40, in which the flanges 4:1, 41 of the kiln sections 11 and 12 arereceived. Such arrangement prevents the passage of gases and air and atthe same time. permits contraction and expansion through a considerablerange. The dotted line 7) represents substantially the level assumed bythe cement forming material in its progress through the section 11 ofthe kiln and through the mill. Since the ground material is deliveredthrough the screen 25* at a lower level than the kiln section 12', itbecomes necessary to provide means for elevating ground cement formingmaterial into the kiln section 12", and for this purpose I may providethe kiln section 12 with a number of spiral chutes Q2 for elevating themateit may fall through the openings 43 into the kiln section 12*, andhelical ribs or shelves ll may be provided in the interior of the kilnsection 12 for directing and delivering the falling material well intothe section 12 The mill section being preferably larger in diameter thanthe kiln sections causes a reduction in draft in such neighborhood,thereby materially reducing dust losses due to the strong kiln draft.Any means of rotating the kiln sections 11 and 12 and the mill section21 'may be utilized and each thereof may be separatelydriven at theappropriate speed. In the form shown the mill section 21 is providedwith tires to by which it is rotatably supported upon rollers 46.

The form of apparatus shown in Fig. 7 differs from that shown in Fig. 5pally in that there is no relative rotary movement between the kilnsections and the mill section, the kiln sections and the mill seeifdesired, and a valve as 37 may tion being formed the screen 25 so thatprincias one continuous structure, all rotating at the same speed.l/Vith such arrangement the mill section is preferably enlarged indiameter over the kiln, sections so as to have a somewhat increasedperipheral speed for doing the grinding work and to cause a localreduction of draft in this neighborhood. The position assumed bymaterial being acted upon is indicated by the dotted line 0. Fordelivering the ground material longitudinally through the screen 25 tothe interior of the kiln section 12, one or more spiral ribs or vanes 47may be provided.

In Fig. 8 T have shown a still further modified form of apparatus inwhich the grinding mill is arranged to surround the kiln. The outercircular wall of the mill 21 is provided with tires 48 which may run onsuitable rollers, and the interior of the kiln 1O is preferably providedwith two spaced flanges ll and let". ings 15 are provided in the kilnsection 11 adjacent to the flange 14:, and the cement forming materialon its passage through the kiln coming in contact with the flange lldrops through the openings 15 into the mill 21,the position assumed byits surface being indicated by the dotted line (Z, and after beingground, is passed out through the screen 25 and is picked up by thepockets l9 on the kiln which communicate with the holes 50 in the kilnsection 12 and inclined longitudinal vanes 51 are preferablyprovided onthe interior of the kiln section 12 for conducting the cement formingmaterial away from the flange 1% alongside of which the openings 50 arearranged. Suitable means for securing tight connections between theparts are provided. and for this purpose I may provide the mill 21 withend sections 52 having preferably inwardly inclined closing rings 58attached thereto and fitting closely about the kiln sections thoughother forms of closure may be made use of.

T may provide means "for cooling the mill somewhat when desired, as byproviding a water sprinkling pipe 5 1, as shown in Fig. 8. for sprayingjets of water on the mill or mill section, but this arrangement is notdesigned to cause any substantial loss of the heat of the cement formingmaterial, but merely to prevent excessive and destructive heating of thepulverizing apparatus.

In Fig. 9 T have shown, diagrammatically. a cement kiln 10. The fuelsupply and clinker discharge end are indicated by reterence letter A,the clinkering Zone ends substantially at the dotted line B. Thepreferred location of the grinding mill with respect to the entirelength of the kiln is indicated at C and the stack and material supplyend at D. The precise relation of the parts may be varied somewhat fromthat A. series of openshown, however, it being important that the millis 50 located as that the calcining of the cement forming material andthe driving off of the carbon dioxid shall havebeen nearly or completelyaccomplished before the material is delivered to the mill, and furtherthat the location of the mill shall be at such distance from the fuelsupply end A as that under no operating conditions shall the clinkeringzone extend so far as to reach the grinding mill.

In operating in accordance with my invention the material for formingcement, which is usually a mixture of high calcium stone and low ornon-calcium stone or clay, is fed to the calcining section of the kilnwhich, asis usual, is arranged at an incline so that upon rotation thematerial will be gradually fed toward the opposite end. Such materialis. not subjected to preliminary grinding but is preferably sufiicientlyreduced in size to pass through the meshes of a one-half inch screen orthereabouts. This fairly coarse material may be raised as by means ofthe shelves 38 and showered to the bottom of the kiln, thus being passedthrough and-through the heated gases as the feeding progresses, thoughthis feature may be dispensed with, if desired. As the material underthe influence of the heat in the kiln becomes heated the moisturecontained expands and is driven off and carried away, and the materialsare more or less broken down by this action and by the various othereffects of heat thereon, and by the time it reaches the grinding mill,all or nearly all of the carbon dioxid is driven off so that the weightof the material is thereby reduced to about two-thirds of the amount fedto the kiln, and the materialis broken down and honeycombed by the heateffects, especially on the outside of separate particles, so that whensubjected to grinding it is readily and rapidly reduced to extremefineness.

Any cores produced in this way which have not yet been calcined in thecalcining zone, are thoroughly exposed to the heat and are calcined, andthus an atmosphere containing carbon dioxid may be created in the millsection which aids greatly in projecting any metal arts and preventingfree oxidation thereof The material being subjected to the grindingoperation while hot, any tendency to clog the mill by the materialbecoming hydrated, as may happen'if it is first calcined and then cooledbefore grinding, is avoided. After passing through the mill the finelydivided materials, in a much finer state than is commercially obtainableby preliminary grinding, are delivered to the clinkering zone of therotary kiln and are cement clinker in the then converted into usualmanner, except that such action is more thorough by reason of thegreater fineness and can be carried on at a somewhat reduced temperaturefrom the usual practice by reason of the facility with which the actionof clinkering. takes place in the finely divided material. 1

According to present practice it is customary to pulverize together themixture of high calcium stone and low or non-calcium stone or clay.'Usually the high calcium content of the mixture is harder and moreresistant to pulverization than the low calcium part; then as these arepulverized together, the low calcium content naturally goes finer thanthe hard or high calcium stone and the majority of the coarser parts ofthe pulverized material are higher in lime than the average of the mass.I have repeatedly had the residue'left on a fine sieve of 200 mesh perinch of a ground mixture of high and low calcareous stone analyzed, andhave found its calcium content to be higher than the average of thematerial before it is passed through the screen. After the material issubjected to the heat of the calcining zone,

the opposite situation is presented, and the calcined particles ofmaterial high in lime content may be finely pulverized more readily thanthe particles of the materials carrying less lime. It is generallyrecognized that the coarse particles of the material high in calciumcontent is what causes cement to be unsound. It is also generallyrecognized, on the other hand, that a too low proportion of lime willcause the cement to be quick setting and slow hardening. With myimproved process, the range between cement which will be on the one handunsound and on the other hand too quick setting and slow hardening, isvery much increased, and the certainty with which sound cement, whichwill not set too quick and harden too slowly, can be produced is of verygreat advantage.

It is to be understood that my invention is not confined to the specificapparatus shown for purposes of illustration, but that modifications anddepartures may be made therefrom, within the scope of my claims, withoutdeparting from my invention or sacrificing any of the advantagesthereof.

Having thus described my invention, what I claim is:

1. In cement apparatus, a rotary kiln section for calcining ungroundcement forming material, a clinkering kiln section substantially in linetherewith, and a rotary grinding mill intermediate the two kilnsections, there being an uninterrupted substantially straight closedpassage through 'the kiln sections and the mill whereby the cementforming material is first calcined, then ground and then clinkered, andthe products of combustion and gases pass continuously and directlythrough the apparatus in the opposite direction.

2. In cement apparatus, a rotary kiln section for calcining ungroundcement forming material, a rotary clinkering kiln section in linetherewith, and a rotary grinding mill intermediate the two kiln sectionsand of a larger diameter, there being a continuous closed passagethrough the kiln sections and mill, and the kiln sections and mill beingeach separately rotatable, substantially as set forth.

In testimony that I claim the foregoing, I

WILLIAM H. MASON. i

Witnesses:

M. A. JoHNsoN, H. TRAUTVETTER.

